I have my own suggestions about the mineral market, but as far as fixing the miners goes here would be my suggestion. Raise the initial build price of all their ships by a significan`t amount (cash only, not minerals). The improve the hull strength and sheilds on all their ships, especially starbases. Ideally, miners should have the weakest offense and the best defense of any race. Generally the strategy for miner is to build a defensive fleet and wait for a retal, then climb to high power and smah your opponent from above. Unfortunately the defense of most miner ships just isn`t good enough to do this unless you are really good at stacking, in which case you probably have bought a paid account and swithced to guardian anyway.